Adjustable post for instrument



l,April 20, 1954 v w. ANGs'r 2,675,732

ADJUSTABLE PosT FOR INSTRUMENT iAssEMBLIEs Filed nec. s, 195o Patented Apr. 20, y1954 .TENT OFFICE ADJUSTABLE POST FOR INSTRUMENT ASSEMBLIESr Walter Angst, Manhasset, N. Y., assignor, by mesne assignments, to Kollsman Instrument Corporation, Elmhurst, N. Y., a'corpo'rati'on of New York Application December 8, 1950, Serial No. 199,809

2 Claims. 1

This invention relates to improvements in precision instruments and provides an improved post construction for spacing the mounting plates of instrument mechanisms between which movable elementsy such as shafts, stems, gears, and other` elements are mounted.

In many instruments, for example clock-works or gear trains, it is not objectionable, if shafts or stems are mounted between the plates with a certain freedom of axial movement. However, there are many instances where the amount of the axial play is critical and requires accurate adjustment. It has been customary in such instances to depart from the convenient construction ofv using the plates themselves as bearings and to provide individual bearings which are adn justable with respect to the mounting plates. This is a somewhat inconvenient, and moreover expensive, procedure involving more parts and more expensive machining.

The invention provides a novel form of spacer which permits the distance of the mounting plates to be easily varied or adjusted within oertain limits thus eliminating the necessity of special adjustable bearings` for shafts or other elements for which the freedom of axial movement is critical.

The objects, features, and advantages of this invention will appear more fully from the detailed description which follows accompanied by drawings showing, for the purpose of illustration', a preferred embodiment of the invention.

v Although the characteristic features of this invention which are believed to be novel will be particularlyv pointed out in the claims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out may be better understood by referring to the following descrip-tion taken in connection with the accompanying drawings forming a part of it in which:

Figure 1 is an elevational view, partly in cross section, of an instrument assembly incorporating' the novel post;

Figure 2v is a cross sectional elevation on an enlarged scale through the post proper; and

Figure 3 is a side view of certain elements shown in Figure l, the view being taken on line 3-3 of Figure l.

In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be as generic in their application as the art will permit. Corresponding reference characters refer to corresponding parts in the several figures of the drawings.

In the drawings accompanying, and forming part of', this specification, certain specific disclosure of the invention is made for the purpose oi explanation of broaderV aspects of the invention, but it is understood' that' the details may be modied` in various respects without departure from the principles of the invention and that the invention may be applied to other structures than the one shown.

The apparatus shown in Figure 1 comprises three mountingA plates II, I2 and I3 between which various instrument elements are mounted. The plates II and I2A are spaced by posts I4 and I5 of conventional construction. A diaphragm capsule assembly It is mountedV on the base plate Il and carries a boss Il engaging an arm I8 of a rocking shaft I9 pivotally mounted in depending lugs one of which is visible at 29..

The rockingV shaft I9 has a further arm 2! extending through an aperture 22 in the plate I2 engaging an arm 23' on a shaft 2li carrying agear sector 25. The shaft 24 is mounted for rotation in bearings 26 and 2 drilled inthe plates I2 and I3' in a conventional manner.

The gear sector 2'5 meshes with the pinion 28 on a shaft 2li. The pinion shaft 29 is spring biased by a conventional hairspring 30 whose outer end is clamped in a post 3| or 32. The hairspring eliminates play and lost motion between the gears and between the engaging arms of the Shaft 24 and of the rocking. shaft IS. The shaft ZS'is shown as having an extension or hand staff' 3?,l extending through the plate I3 for the support of a pointer or other indicating element (not shown) The spacing of the plates I2 and I3 must obviously be greater than the distance between the thrust surfaces 36' and 35 of. the shaft 24 to provide for the necessary freedom of rotation. It is apparent, however, that the axial play d of the shaft 2.5 may be the cause of rotation of the shaft 33 without an accompanying movementv ofk the diaphragm capsule if, due to vibration, shock, or other causes the shaft 2&3 shifts axially so that the play is` eliminated at 34 and is present at 35. Such axial shifting of the shaft 24 permits. the shaft 29 to turn due to the variation in the angular engagement between the arms 2| and 23 which are maintained in contact by the biasing action of the hairspring. It is thus evident that the conventional mounting of shafts in holes drilled in the supporting plates may become a source of errors in the indication.

The invention provides a simple and improved form of spacer or post permitting adjustment of the distance between two mounting plates to an extent sufficient to reduce the aforementioned axial play and the resultant errors to a permissible minimum.

This is accomplished by installation of at least one post whoseoverall length may be reduced by an amount necessary to reduce the axial play of the critical shaft. The post is preferably placed closely to the critical shaft in order to reduce the range within which the post must be adjustable. This post or spacer is shown at 35 in Figure 1 and is shown in enlarged cross sectional View in. Figure 2.

The post comprises a body 31 of either round or polygonal cross section. The post has an internal bore, the bore being screw-threaded at one end of the post as shown at 38 and being plain, and of larger internal diameter, at the other end of the post as shown at 39. The body has plate engaging shoulders 40 and 4I. One of the shoulders, 135, is shown as being of greater length than the other for permanent attachment to the plate i2 'by riveting, spinning or heading over in a manner well known per se in the instrument art.Y The other shouldered end M may be shorter for attachment of the mounting plate i3 by a screw L32. rIhe screw may be of the machine screw type comprising a head 43 and a threaded stern lill. The threaded stern passes freely through the plain bore 39 without Screwthread engagement, but engages the threaded portion of the bore 38.

Slots 45 and t6 extend into the body of the post within the plain-bore-portion and extend preferably beyond the bore proper as shown at 4'! and 4.5. The slots are longitudinally spaced with respect to the post and are also circumferentially spaced. In the event two slots are employed, the slots are oifset 180 degrees with respect to each other. If three slots are used, it is advantageous to offset them 120 degrees with respect to one another.

It is apparent from Figure 2 that tightening of the screw 42 first presses the mounting plate I3 rmly against the shoulder 4l. Continued tightening of the screw causes the plate I3 to move closer towards the plate i2, within the freedom permitted by the slots. In the illustrated embodiment the maximum reduction in length of the post 38 is approximately equal to the width of one of the slots d5, 56.

Returning now to Figure 1 it is evident that by tightening of the screw d2 the axial play d of the shaft 2li may be reduced to any desired extent. It is normally net necessary that all the posts between the plates I 2 and I3 are of the novel adjustable type. The post 49, for example, may be a conventional post of a xed length. In such a oase the post llS acts as a fulcrum about which the mounting plate I3 tilts. Nevertheless, all the posts 49 may be of the type shown at 36.

Obviously the present invention is not restricted to pressure responsive instruments but has general application to other forms of precision instruments, including clocks in which the axial freedom of the balance wheel may thus be adjusted.

What is claimed is:

1. An adjustable post for spacing a pair of plates; said plates having aligned openings; said post having a diameter substantially larger than the openings and extensions at each end of smaller diameter than the openings and introducible into said openings; said extensions dening shoulders against which said plates may rest; means for securing one of said extensions to one of said platesV at the opening in said one plate; said post having a longitudinal bore; the interior of said bore being threaded adjacent said one end of said post which is securable to said one plate; the bore being substantially smooth for a substantial portion thereof adjacent the other end; a transverse slot in said post extending through the material of said post surrounding the smooth portion of said bore and communicating with the periphery of said post; a screw having a` head engaging the outer surface of said other plate at the opening therein and extending through the extension at the other end of the post; said screw passing through the smooth portion of the bore and engaging the threaded portion thereof; rotation of said screw after the head engages the said other plate collapsing the post at said slot and decreasing the distance between the plates. Y

2. An adjustable post for spacing a pair of plates; said plates having aligned openings; said post having a diameter substantially larger than the openings and extensions at each end of smaller diameter than the openings and introducible into said openings; said extensions dening shoulders against which saidv plates. may rest; means for securing one of said extensions to one of said plates at the opening in said one plate; said post having a longitudinal bore; the interior of said bore being threaded adjacent said one end of said post which is securable .to said one plate; the bore being substantially smooth for a substantial portion thereof adjacent the other end; a plurality of transverse spaced parallel slots in said post; each Vslot extending through the material of said post surrounding the smooth portion of said bore and communicating with the periphery of said post at angularly diierent positions; a screw having a head engaging the outer surface of said other plate at the opening therein and extending through the extension at the other end of the post: said screw passing through the smooth portion of the bore and engaging the threaded portion thereof; rotation of said screw after the head engages the said other plate collapsing the post at said slots and decreasing the distance between the plates.

References Cited in the file of this patent.

UNITED STATES PATENTS 1 Goshia Sept. 26, 1944 

